It will be a "cut-throat" situation when Alastair Cook's two prospective England Test opening partners each try to grasp their opportunity against Mumbai A.

With Cook rested, Nick Compton and Joe Root are set to open the innings together at the Dr DY Patil Sports Academy.

They will do so with a direct conflict of interests.

Both have their eyes on a Test debut in Ahmedabad on November 15, and surely only one will get his wish.

The stakes will be high, and nerves inevitable, for the young Yorkshireman and slightly older South Africa-born Somerset batsman when they take guard.

One slip could prove very costly, especially for Compton who made a third-ball duck on debut for England in the tour opener against India A at the Brabourne Stadium when he was granted a first chance ahead of Root three days ago.

Cook does not try to disguise the stark truth, that Root and Compton will be batting together and yet against one another at the same time.

"This game and the next game we will decide," he said.

"It's a cut-throat business. You're trying to pick the best player to do it, and they've both got an opportunity to score runs and push their claim.

"So that's what it is. I think they both know the situation."

Compton failed his first audition, pushing forward and edging an outswinger behind.

"That's cricket," said Cook.

"(It was) a decent ball, with the new ball.

"It proved to us that in the first eight or nine overs we've got to be right on it, because the new ball can do enough, and as a batting side (we have to) make sure we can get through that first hour when it does swing and then settle down as the ball gets older."

Although 29-year-old Compton, grandson of the great Denis, got first run on Root by being picked for the opening match, Cook insists there is not yet any pecking order.

"It was totally open.

"Both (coach) Andy (Flower) and I haven't seen a huge amount of either.

"I've played against Nick a couple of times - and I played in Joe Root's first ever game, a one-day game.

"It was important we came here with a clear mind. I think we've done that."

Root's inexperience will not count against him either, if England think he is showing them the right signals.

"He wouldn't be in the squad if we didn't think he was ready to play," added the captain.

"They're at different stages of their career.

"One's far more experienced and has got more runs behind him; the other one's a lot younger and has impressed everyone at every stage of his career.